Cumulus Support

Bernd wrote:Steve you wrote that the speed would still be logged at 1-minute intervals.
Does this mean that into the logs (or wherever the datas are stored) the interval
is still 1 min, also i set it to (for example) 10min into station setup?
So there is the chance for me to calculate with this stored datas.

Cumulus writes to the logs at the interval you set in the station setup - I assumed you were using 1 minute, as you mentioned this. This is completely independent of the logging interval that you have set in the station, which Cumulus has no control over.

But the energetic content into both cases is highly different, although is goes in both cases
out to average 4m/s. Thats coming out to the fact that double the windspeed means 8 times
the power into the wind.

Right, I understand.

So for accurate calculations of how much power was into the wind i must have many measurements.
I was happy to notice that the wh1080 is able to deliver a snapshot every 48 seconds.

Davis stations give wind readings every three seconds

A thought occurred to me - perhaps the forecast shouldn't be updated so often, maybe just once an hour. Of course, all this would do is 'smooth out' the forecast, rather like the average wind calculation, so who is to say that the forecast on the hour is any better than a forecast at any other time. I believe this algorithm is really only supposed to be used once a day anyway, at 0900.

Cumulus writes to the logs at the interval you set in the station setup - I assumed you were using 1 minute, as you mentioned this. This is completely independent of the logging interval that you have set in the station, which Cumulus has no control over.

Well, i understand it like that and i'm not sure that i understand it correct :
Into the wh1080 setup itself i can only set the loging time to a minimum of 5 minutes.
Nevertheless Cumulus does take a loging interval that i set into cumulus station setup,
for example 1min. Also the forecast than will calculate every 1min.
If i set the interval into Cumulus to 1 min, but also do set " calculate 10 min wind average", than Cumulus
logs the windspeed (and all other datas) every minute into the log data, but for the calculation of the
forecast and for the graphs it uses the 10 min average, correct ?

Davis stations give wind readings every three seconds

WOW.... are you sure ? So the transmitter batteries must be empty very quickly ?

A thought occurred to me - perhaps the forecast shouldn't be updated so often, maybe just once an hour.

Yes i agree to you if then the average values of the "forecast calculation interval" would be used for calculation.
I think half an hour or one hour would be much better than a forecast every loging interval.
I think the station forecast does it like this way, at least it changes rarely.
You are right that the forecast matching would not (much) been rising up then, but it's much better to
see the forecast beeing stable instead of changing permanetly between some of the 26 messages
to confuse the user.


Bernd

Bernd wrote:If i set the interval into Cumulus to 1 min, but also do set " calculate av windspeed every 10 min", than Cumulus
logs the windspeed (and all other datas) every minute into the log data, but for the calculation of the
forecast and for the graph it uses the 10 min average from that data, correct ?

That's right; the logging interval has no connection with the time over which the wind speed average is calculated.

WOW.... are you sure ? So the transmitter batteries must be empty very quickly ?

It lasts quite a long time. The transmitter has a solar panel, a large capacitor, and a Lithium battery. During the day, the transmitter is powered by the solar panel and the solar panel also charges up the capacitor. During the night, the transmitter uses the power in the capacitor. If it hasn't been very sunny and the capacitor runs out of charge during the night, it switches over to the battery. So the battery is only used as a last resort. Even with no sunlight at all, the battery would last a year.

I think a half hour or one hour would be much better than a forecast every loging interval.
Also the station forecast does it like this way.

The Davis forecast also updates once an hour. I think I will probably change Cumulus to do the same...

steve wrote:A thought occurred to me - perhaps the forecast shouldn't be updated so often, maybe just once an hour. Of course, all this would do is 'smooth out' the forecast, rather like the average wind calculation, so who is to say that the forecast on the hour is any better than a forecast at any other time. I believe this algorithm is really only supposed to be used once a day anyway, at 0900.

I for one like to see the forecast so I'm glad you have added the feature but I can understand that you might regret this at times. I think your idea of reducing the update frequency is a good one and it has my vote. It would seem that this approach is adopted by the Davis stations as it appears to have a forecast that it sticks with for quite some time (in fact I think the one in Cumulus is often more accurate ). Perhaps it should be a user defined variable but I’ve no idea how much effort either option would entail.

It sounds like that the davis station is what i should use for my windenergie measurements.
But if i remember right, it was 10 times more expensive... ?

Steve if you would change the forecast intervall like you said (or do integrate this new feature),
that would be very fine and would rise up the whole quality of Cumulus a little bit more.

And i'm happy that there are still 1 min logging datas, regardless what i set about average wind
speed values. ( i hope i have understand this right, sorry for my bad english)

Bernd

nking wrote:

steve wrote:A thought occurred to me - perhaps the forecast shouldn't be updated so often, maybe just once an hour. Of course, all this would do is 'smooth out' the forecast, rather like the average wind calculation, so who is to say that the forecast on the hour is any better than a forecast at any other time. I believe this algorithm is really only supposed to be used once a day anyway, at 0900.

I for one like to see the forecast so I'm glad you have added the feature but I can understand that you might regret this at times. I think your idea of reducing the update frequency is a good one and it has my vote. It would seem that this approach is adopted by the Davis stations as it appears to have a forecast that it sticks with for quite some time (in fact I think the one in Cumulus is often more accurate ). Perhaps it should be a user defined variable but I’ve no idea how much effort either option would entail.

Hi Steve,

Is your idea for forecast frequency a possible Cumulus 1 enhancement or Cumulus 2? Does it need to be added as an enhancement request, if so, would you like me to do this?

On a slightly off topic point, I wanted to send you a file (18Mb) from my OU course which I thought you might like - how best can I do this as PM is out of action?

nking wrote:Is your idea for forecast frequency a possible Cumulus 1 enhancement or Cumulus 2? Does it need to be added as an enhancement request, if so, would you like me to do this?

As it's a simple change (famous last words) I can do it in Cumulus 1, so if you could please create an enhancement request so I don't forget, that would be good.

On a slightly off topic point, I wanted to send you a file (18Mb) from my OU course which I thought you might like - how best can I do this as PM is out of action?

Send it to steve@sandaysoft.com, please.

Hi Steve,

You managed to make the update before I'd filled in the request - what service

Just out of interest when does the update hourly occur, is it a timer counting down or on the hour?

nking wrote:Just out of interest when does the update hourly occur, is it a timer counting down or on the hour?

It should do an initial forecast when it starts up, and then on the hour after that.